Shared Flashcard Set

Details

MCB-2 Block-3 Gems-3
NADPH, Non-Glucose Metabolism
21
Microbiology
Graduate
07/04/2011

Additional Microbiology Flashcards

 


 

Cards

Term
NADPH and ribonucleosides
Definition
Ribonucleosides -> Deoxyribonucleosides
Via Ribonucleotide reductase.
(Active in SH state, inactive = S-S. Oxidized)

Rionucleotide reductase maintained in proper state by thioredoxin reductase.
Uses NADPH
Term
Glutathione Structure
Definition
Made of Glu(tamate), Cys, Gly Sulfhydral groups on cysteine residues are reduced y NADPH Value of SH group keeps other cysteine groups in reduced states Glutathione reduce these thio groups non-enzymatically
Term
Glutathione in RBC
Definition
Excess S-S bonds may form and produce Heinz bodies Heinz bodies attach to membrane and make it less pliable Leads to RBC removal/hemolysis Glutathione peroxidase requires Se as a cofactor. 2GSH + H202 -> GSSG + H2) Glutathione reductase: GSSG + NADPH -> 2GSH + NADP
Term
Glutathione-S-Transferase
Definition
Located in Liver

Attaches glutathione to toxic molecules making them more soluble.
Term
Glutathione and acetaminophen
Definition
CYP-450 breaks down acetaminophen into toxic byproduct which is cleared by glutathione.

Too much acetaminophen and glutathione runs out.

HIghly reactive intermediates formed, liver damage within 24-48 hours.

~35% of severe liver failure
Term
Ascorbic Acid(Vit C)
Definition
Oxidized Vitc C is recycled by acquiring electrons and H+ from reduced glutathione(GSH)

Vit C is an antioxidant.

Diffusible oxidants -> Reduced(harmless) oxidants
Term
NADPH's role in NO synthesis
Definition
L-arginine + O2 + NADPH -> Citrulline + NO + NADP.

Via Ca+ dependent enzyme

NO is vasodilator -> cGMP -> Muscle relaxation.

Viagra inhibits guanylate phosphodiesterase
Term
G-6-P Deh deficiency
Definition
NADPH generation in RBC diminished -> Heinz bodies.

May only be symptomatic when drugs are taken.

Fava beans -> Divicine(strong oxidant)
Quinoids -> severe hemolytic anemia only affected males.
Term
G-6-P Deh Deficiency and Malaria
Definition
Plasmodium falciparum is sensitive to oxidative damage.

Mutatoin in G-6-P has partially beneficial effect.

Red blood cells die earlier.
Term
Superoxide Dismutase
Definition
In cytosol uses Zn and Cu to capture superoxide.

In mitochondrira Mn and Cu used to capture superoxide.

Superoxide(O2-) -> H202

Way more enzyme than substrate(super oxide)
Term
Catalase
Definition
Contains heme and Fe++ in peroxisomes filled with H2O2

1/4 alcohol broken down by catalase, rest by alcohol deh.

Only 1 membrane bi-layer
Term
Amyotrophic Lateral Sclerosis(ALS)

Lou Gehrigs disease
Definition
Enzyme defect cytosolic superoxide dismutase

REquires Zn and Cu

Neurodegenerative

Motor neurons affeted.

Sensory nerves and ANS remain intact
Term
Aldolase B defieincy
Definition

Km for FBP is lower than Km for F-1-P F-1-P can accumulate In deficiency: fructose intolerance/ poisoning. F-1-P is trapped in cell. Hypoglycemia, Vomiting, Jaundice

 

Aldolase B normally: F-1-P -> Glyceraldehyde

Term
Activation of Sugars
Definition
UDP: Glc and derivatives
GDP: Mannose
CMP: Sialic acid - NANA
Term
Sorbitol Metabolism
Definition
Glucose -> sorbitol. Uses NADPH and aldose reductase

Sorbitol + NAD -> NADH + fructorse via sorbitol deh. (active in seminal vesicles)

Fructose by-passes insulin-dependent glut and isomerase rxn.

production of sorbitol favored by high NADPH/NADP
Term
Effects of hyperglycemia on sorbitol metabolism
Definition
During hyperglycemia glucose enters, lens, retina, etc.

Water followws sorbitol into cell

Glucose -> sorbitol and is trapped inside cell.

Water retention, retinopathy, cataracts, peripheral nerve damage
Term
Galactose Metabolism
Definition
Lactose = dimer of glucos & galactose in B1,4 linkage

Gal + ATP -> Gal-1-P + ADP via galactokinase

UDP-glucose + Gal-1-P -> G-1-P + UDP-galactose via Gal-1-P uridyl transferase.
Term
Gal-1-P uridyl transferase deficiency
Definition
UDP-glucose + Gal-1-P -> G-1-P + UDP-galactose.

Galactosemia(similar to fructose intolerance but more tissues affected)

Galactose -> galactitol -> Cataract formation and nerve damage
Term
Functions of UDP-galactose
Definition
Important in formation of Lactose

Lactase synthase: Galactosyltransferase and α-lactalbumin.

UDP-Gal + glucose -> Lactose
Term
Regulation of UDP-galactose
Definition
Protein A: transferase in most tissues.
UDP-Gal + N-acetylglucosamine -> N-acetyl-lactosamine
Important in structural elements of N-linked(asparigine) glyco proteins

Protein B: α-lactalbumin found only in lactating mammary tissue.

Progesterone inhibits Protein B synthesis

Prolactin stimulates α-lactalbumin synthesis. A/B units combine
Term
UDP-glucuronate
Definition
UDP-Glucose -> UDP-glucuronate via UDP-glucose deh

UDP-glucouronate allows glucouronate to be attached and makes compounds polar(soluble)

Important for heme degradation (billirubin is insoluble)

Deficiency of bilirubin-glucuronyl transferase -> Jaundice
Supporting users have an ad free experience!